1. Field of the Invention
This invention relates to underground utility pipe installation apparatus and, more particularly, to pipe pullers for plastic utility pipes.
2. Prior Art
In installing utility pipes, for example heating gas pipes from the mains into the individual houses, it is necessary to bore a passageway for the pipe through the earth since all such pipes are subterranean. A bore-pipe is used for this purpose and after it completes the job of boring the tunnel for the utility pipe, it is the practice to connect a pipe to the boring tool in preparation for pulling the pipe through the tunnel which has been formed so that when the bore-pipe is withdrawn the utility pipe is drawn into the opening formed by the bore-pipe. In the past, this has been accomplished with what is known as a "Kellum" puller. The "Kellum" puller has a wire mesh "Chinese finger" which grips the utility pipe as it is pulled back through the pipe-bore-hole. Field experience has shown that the "Kellum" puller, because of the mesh construction of the puller permits dirt to pass into the utility pipe, thus restricting the flow of gas or other fluid through the pipe and the wire mesh which makes up the puller also becomes frayed and difficult to handle. That wire mesh may become coated with mud in some cases during the pulling process and when that occurs the cleaning process for the tool may be difficult and time-consuming. In sandy soils the mesh, which forms the conventional puller, can become packed with sand which, again, causes difficulty in pulling the utility pipes through the bore-hole.
Furthermore, with the conventional or "Kellum" puller, there is no specific means provided for attaching the locating wire which must accompany the plastic pipe when it is installed as a utility pipe. This locating wire is necessary so that, in the event of an emergency, an electronic detector may be utilized to locate the utility pipe in the ground. Of course, when leakage of the utility pipe occurs, finding and repairing that pipe is vital.
Furthermore, in connection with the boring-tool known as the "Accupunch" tool, there is no attachment provided for pulling the utility pipe through the bore-hole formed by the Accupunch tool. An Accupunch tool is one which uses compressed air to force the nose of the tool forward, forming a bore-hole. This tool, which relies upon the use of compressed air to compress the soil and form the bore-hole, is only appropriate in certain soil, such as sandy loam, which is not densely packed. When the Accupunch tool, or its equivalent, is used, the plastic pipe is taped directly to the air hose, along with the locating wire, and the utility pipe and the locating wire are pulled back through the bore as the compressed-air tool is removed from the bore. The attachment of the pipe and the locating wire to the Accupunch tool is sometimes difficult and time-consuming.
Therefore, it is an object of this invention to provide an improved puller for plastic utility pipes.
It is a further object of this invention to provide an improved puller for plastic utility pipes which saves time in its use and assures maximum performance of the utility pipe after it is installed under the ground.